Process of making alkyl sulfuric acid



Patented D60. 6, 1921.

G. P. ADAMSON. PROCESS 0F MAKING'ALKYL SULFRIC ACID.

APPLICATION FILED IuIIE 29, 1920.

LL It e UNITED STATES PAT ENT oFFi'cE.

GEORGE P. ADAMSON, OF HUNTINGTON, NEW YORK, ASSIGNOB T0 GENERAL CHEM- IOAL COMPANY, OF NEW YORK, N. Y., A CORPORATION-OI' NEW YORK.

PROCESS OF IAKING .ALKYL SULFURIC ACID.

Specification of Letters Patent.

Application led June 29, 1920. Serial No.' 392,734.v

To all whom t may concern Be it known that I, GEORGE P. ADAMsoN, a citizen of the United States, and resident of Huntington, Suffolk county, New York, have invented a certain new and useful Process of Making Alkyl Sulfuric Acid, of which the following is a specification.

The invention relates to the production of alkyl sulfuric acid (and in the first instance methyl sulfuric acid and ethyl sulfuric acid) and its object is to enable the production thereof to be carried out on simple, economical and efficient lines by means of which the many disadvantageous results of the known methods of combining such alkyl alcohol and sulfur trioXid may be avoided.

Various processes have been suggested for the production of alkyl sulfuric acid from an alkyl alcohol and sulfuric anhydrid, the latter being supplied or added to a givenv volume of alkyl alcohol either in the form of a gas or in the forni of fuming sulfuric acid. When the sulfuric anhydrid is added as fuming sulfuric acid the anhydrid is in solution in sulfuric acid, and consequently ay considerable amount of sulfuric acid remains in Ithe product. On the other hand the direct reaction between an alkyl alcohol and sulfuric anhydrid gas is diiiicult to control and tends to cause erratic variations of temperature resulting in the loss of alcohol as vapor. Even the use of a very low temperature does not prevent the loss of alcohol. lt has been proposed to use carbon tetrachloiid as an inert diluent in which the reaction may take place, but the economical operation of this process necessitates the removal and recovery of the carbon tetrachlorid from the product obtained.

ln my new process the reaction between the alkyl alcohol and sulfuric anhydrid is easily controlled and erratic fluctuations of temperature are avoided. The quality of the product may be maintained as a constant within narrow limits. No ihert material is introduced which must later be removed from the product, nor is there present a large amount of sulfuric acid as is the case when the alcohol reacts with fuming sulfuric acid. The temperature at which the reaction takes place is easily maintained and there is substantially no loss of alcohol as vapor, while the sulfuric anhydrid is almost completely absorbed in the bath. The whole process r'uns smoothly and requires little supervision. I have discovered that all of these various advantages may be secured and the numerous disadvantages of other processes overcome provided the alkyl alcohol and the sulfuric anhydrid are not brought together directly but the alcohol introduced simultaneously or successively with Patented Dee. le, 1921; Y

the sulfuric anhydrid into a bath or domii nant body of the corresponding alkyl sul`v furic acid which it is desired to produce, the gate of iiriltrgdicton of the alcohol and suluric an y ri ein a ro riatel re lated and suitable tmplatlrfre cofiditifis maintained in the bath.

'lflie following description of one specific method which l have used successfully for making methyl sulfuric acid illustrates the principles of my invention, but l wish to be understood asnot limiting myself t0 the details described, for these can be variously changed without departing from the invention.

The accompanying drawingillustrates diagrammatically apparatus adapted for the carrying out of the invention.

ln starting this process a suitable vessel a is' made to contain a given quantity of methyl sulfuric acid. lnto the methyl sulfuric acid in the reaction vessel a are introduced simultaneously, and in the proper proportions for combining, methyl alcohol (through pipe b) and so-called contact gas (sulfuric anhydrid manufactured by the contact process and containing about 8% S03) throughpipe o. The vessel a is, of course, suitably lined with roper brick work al and is provided with t e exhaust m. rllie methyl alcohol is introduced into the bath through an inlet near the bottom of the reaction vessel a, and the contact gas is forced in througlia number of small openings e above the alcohol inlet and rises in the liquid. These openings are shown as drilled at the top, bottom and sides of the conduit for the contact gas which is suitably supported in saddles n. The liquid is cooled by means of' water circulating through it in coils f s o that the temperature is kept below 150o F. preferably at 100O F., any required regulation being indicated by the thermometer k. The specic gravity of the product, when the operation is properly conducted, should be 1.5, and may be observed by lmeans of a hydrometer p floating in the liquid in. i the overflow pipe g and Covered by a glass njai".l The meth l sulfuric acid flows from the apparatus t rough outlet pipe i preferably on its `top surface. The vessel a 1s prolvided with a glass sight hole and the glass sul-furicanhydrid, or'of the methyl alcohol or of both. The as esca ing `Yfrom the reaction vessel shou d be co orless, as a -white anhydri about 8.15

fume -indicates an excess of alcohol or of sulfuric anhydrid. Methyl sulfuric acid which I'obtained'by this process contained er cent. .free sulfuric acid, and was suitalile for 4one of its common industrial uses, namely, the production of dimethyl sulfate.

Eth l sulfuric acid is 'manufactured' in a simi ar manner, using a bath of ethyl-sulfuric acid into which are introduced ethyl alcohol and contact gas. The specific gravity of the product'is maintained at about-'1.3. The ethyl ,sulfuric acid obtained'may contain as much as twelve per cent. of free sulfuric acid and thirteen per cent. of ethyl sulfate.

rlhe details of the process described may be varied if desired, as for instance, by using puresulfuric anhydrid in place ofthe socalled contact gas,`or, instead of adding the sulfuric anhydrid and alkyl alcohol simultaneously, an excess of sulfuric anhydrid may be added, then sufficient `alkyl alcohol run -in to combine with such excess, and the desired amount of alkyl sulfuric acid obtained b successive additionsv of sulfuric and alkyl alcohol. This latter variation of my process is referable .to that wherein a large 'excess o alcohol is first added and the sulfuric' anhydrid then introduced, as in this case the absorption of the sulfuric anh drid may be incomplete and alcohol may e lost as vapor.

In starting the vprocess the first step is to setup the bath or dominant body of the alkyl sulfuricacid of the desired ultimate constitution for the regular production of further quantities oif such alkyl sulfuric acid. Incase a supply of this material is not at hand available for the iillin of the reaction vessel the following metho may b e pursued.

A small amount of methyl sulfuric acid is first made` b passing sulfuric anhydrid into methylalco o ata ow temperature, for example, 25 F. A large percentage of the alcohol is lost at the start, but the absorption becomes better 'as methyl sulfuric acid is formed. To the lmethyl sulfuric acid thus formed small sluivalent amounts of methyl alcohol, and furie anhydrid are addedi withdrawing a Lacasse successively until sufficient methyl sulfuric acid has' been made to start the process.

The invention is capable of being carried out in many different forms of apparatus and ma be modified 'in so many particulars 'of 'detailed execution that I desire to make it clear that the invention is claimed broadly in such a way as to include the use of the many different possible forms of apparatus or of variation in detail; but whenever in my claims-I make mentionspecificall of methyl alcohol or methyl sulfuric acid inl tend such claims to be understood as includin i ethyl alcohol and ethyl sulfuric acid.

at I claim is: 'o' l .1. The process of making alkyl sulfuric acid which.comprises establishing a dominant bath of the desired alkyl sul uric acid, introducing to said bath alkyl alcohol, introducing sulfuric anhydrid, and withdrawing a part of the alkyl sulfuric acid while retaining a suicient volume thereof to constitute a dominant bath within which to y continue the described process.

2. The process of making alkyl sulfuric acid which comprises 'establishin a dominant bath of ,the desired alkyl sul uric acid,

introducing to said bath alkyl alcohol, introducin a contact gas, being a gas containing a out 8% of sulfuric anhydrid, and part of the alkyl sulfuric acid while retaining a sufiicient volume thereof to constitute a dominant bath with- 'in which to continue the described process.

3. The process ofl making alkyl sulfuric acid which 'comprises establishing a dominant bath of the desired alkyl sulfuric acid, introducing to said bath alkyl alcohol, introducing sulfuric anhydrid, the alcohol land sulfuric anhydrid being supplied in `combining proportions with regard to the constitution of the bath, and withdrawing a part of the alkyl sulfuric acid while retaining a sufficient volume thereof to constitute a dominant bath.within which to continue theV described process.

4. The process of making alkyl sulfuric acid `which comprises establishing a dominant bath of the desired alkyl sulfuric acid and then introducing to' said bath alkyl alcohol and sulfuric anhydrid', causing the introduced material' to combine in said bath andmaintainin the temperature of the bath at approximately 100-150 F. more or less.

5. The process of making alkyl sulfuric acid which comprises establishing a dominant bath of the desired alkyl sulfuric acid and then continuously introducing to said bath, al l alcohol and sulfuric anhydrid, cooling t e bath and maintaining its temperature at less than the natural reaction.

temperature of the introduced material and continuously drawing oil' the product.

6. Th rocess of making methyl sulfuric acid wh consists in establishing a dominant bath of methyl sulfuric acid and than' introducing to said bath methyl alcohol .and sulfuric anhydrid, causing the introduced material to combine to methyl sulfuric acid in said bath and maintaining the temperature of the bat-h at approximately 10G-150 F. more or less.

7. The process of making methyl sulfuric acid. which consists in establishing a dominant bath of methyl sulfuric acid cooling said bath and then continuously introducing to said bath, methyl alcohol and sulfuric anhydrid, continuously drawing olf the product and maintaining the specific gravity of the product as withdrawn at a predetermined point by regulating the supply of incoming methyl alcohol and sulfuric anhydrid.

8. The process of making alkyl sulfuric acid which comprises establishing a dominant bath of the desired alkyl sulfuric acid, introducing to said bath at a low level thereof alkyl "alcohol, introducing at a higher level in said bath a s containing sulfuric anhydrid, and with rawing apart of the alkyl sulfuric acid while retaining asullicient volume thereof to constitutev a dominant bath within which to continue the described process. Y

9. The process of making alkyl sulfuric acid which comprises establishing a dominant bath of the desired alkyl sulfuric acid, introducing to said bath at a low level thereof alkyl alcohol,introducing at a higher level in said bath and at a multiplicity of places therein a gas containing sulfuric anhydrid, and withdrawing a part of the alkyl sulfuric acid 'while retaining a sullicient volume thereof to constitute a dominant bath within' which to continue the described process.

In testimony whereof I have hereunto set my hand.

GEORGE P. ADMsoN. 

